• Journal of Microbiology and Biotechnology
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• 제28권4호
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• pp.571-578
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• 2018

Biofuel production using lignocellulosic biomass is gaining attention because it can be substituted for fossil fuels without competing with edible resources. However, because Saccharomyces cerevisiae does not have a ${\text\tiny{D}}$-xylose metabolic pathway, oxidoreductase or isomerase pathways must be introduced to utilize ${\text\tiny{D}}$-xylose from lignocellulosic biomass in S. cerevisiae. To elucidate the biochemical properties of xylose isomerase (XI) from Piromyces sp. E2 (PsXI), we determine its crystal structure in complex with substrate mimic glycerol. An amino-acid sequence comparison with other reported XIs and relative activity measurements using five kinds of divalent metal ions confirmed that PsXI belongs to class II XIs. Moreover kinetic analysis of PsXI was also performed using $Mn^{2+}$, the preferred divalent metal ion for PsXI. In addition, the substrate-binding mode of PsXI could be predicted with the substrate mimic glycerol bound to the active site. These studies may provide structural information to enhance ${\text\tiny{D}}$-xylose utilization for biofuel production.

• 미생물학회지
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• 제32권1호
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• pp.12-19
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• 1994

Saccharomyces cerevisiae의 KEMI 유전자는 세포의 영양 상태에 따라 spindle pole body나 microtubules의 기능을 조절하는 것으로 알려져 있다. 이 유전자 산물의 세포내 분포 및 기능을 규명하기 위하여, KEM1::lacZ 융합 유전자를 제조하였다. 즉, 클론된 KEM1 유전자에 대장균의 ${\beta}$-galactosidase 구조유전자를 갖는 mini-Tn10-LUK element를 무작위 삽입한 pool을 제조하고, 이를 분석하여 KEM1의 기능 부위가 약 3.5kb에 해당함을 확인하였고, KEM1의 기능이 살아있는 KEM1::lacZ 융합 유전자의 클론을 선별하였다. 이 클론을 ${\beta}$-galactosidase 항체를 이용한 indirect immunofluorescence 방법으로 분석하여 KEM1::lacZ 융합 단백질이 핵주변에 위치함을 확인하였다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.290-292
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• 2004

Heavy metal contamination has been increased in aqueous environments near many industrial facilities, such as metal plating facilities, mining operations, and tanneries. The soils in the vicinity of many military bases are also reported to be contaminated and pose a risk of groundwater and surface water contamination with heavy metals. The biological removal of metals through bioaccumulation has distinct advantages over conventional methods; the process rarely produces undesirable or deleterious chemical byproducts, it is highly efficient, easy to operate and cost-effective in the treatment of large volumes of wastewater containing toxic heavy metals. In addition, a recent development of molecular biology shed light on the enhancing the microorganism's natural remediation capability as well as improving the current biological treatment. In this study, characteristics of the cell growth and heavy metal accumulation by Saccharomyces cerevisiae strains expressing phytochelatin syntahse (PCS) gene were studied in batch cultures. The AtCRFI gene was demonstrated to confer substantial increases in metal tolerance in yeast. PCS-expressing cells tolerated more Cd$^{2＋}$ than controls.

• BMB Reports
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• 제34권5호
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• pp.428-433
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• 2001

A defect in uvsC of Aspergillus nidulans caused high methyl methansulfonate (MMS)-sensitivity, hyporecombination, and a lack of UV induced mutation. The uvsC gene of Aspergillus nidulans shares a sequence similarity with the RAD51 gene of Saccharomyces cerevisiae. In this study, in vitro and in vivo tests were conducted in order to determine whether or not the UVSC protein had functional similarities to RAD51, the recombination enzyme in yeast. The purified recombinant UVSC protein, following expression in Escherichia coli, showed binding activity to single-stranded DNA (ssDNA), when both ATP and magnesium are present. In addition, ATPase activity was also demonstrated and its activity was stimulated in the presence of ssDNA. The UVSC protein that was expressed under the ADH promoter in S. cerevisiae suppressed in part the sensitivity to MMS of the rad51 null mutant. Similarly, when the uvsC cDNA was expressed from the nmt promoter, the MMS sensitivity of the rhp51 null mutant of Schizosaccharomyces pombe was partially complemented. These results indicate that the A. nidulans UVSC protein is a functional homologue of the RAD51 protein.

• Biotechnology and Bioprocess Engineering:BBE
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• 제2권2호
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• pp.90-93
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• 1997

Recombinant exoinulinase was partially purified form the culture supernatant of S.cerevisiae by(NH4)2SO4 precipitation and PEG treatment. The purfied inulinase was immobilized onto Amino-cellulofine with glutaraldeyde as a cross-linking agent. Immobilization yield based on the enzyme activity was about 15%. Optimal pH and temperature of immobilized enzyme were found to be 5.0 and 6$0^{\circ}C$, respectively. The enzyme activity was stably maintained in the pH ranges of 4.5 to 6.0 at 6$0^{\circ}C$. 100% of enzyme activity was observed even after incubation for 24 hr at 6$0^{\circ}C$. In the operation of a packed-bed reactor containing 412U inulinase, dahalia inulin of 7.5%(w/w) concentration was completely hydrolyzed at flow rate of 2.0mL/min at 6$0^{\circ}C$, resulting in a volumetric productivity of 693 g-reducing sugars/L/h. Under the reaction conditions of 1.0mL/min flow rate with 2.5% inulin at 6$0^{\circ}C$, the reactor was successfully operated over 30 days without loss ofinulinase activity.

• Journal of Microbiology
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• 제45권1호
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• pp.34-40
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• 2007

In budding yeast, G2/M transition is tightly correlated with bud morphogenesis regulated by Swel and septin that plays as a scaffold to recruits protein components. BNI5 isolated as a suppressor for septin defect is implicated in septin organization and cytokinesis. The mechanism by which Bni5 regulates normal septin function is not completely understood. Here, we show that Bni5 phosphorylation is required for mitotic entry regulated by Swel pathway. Bni5 modification was evident from late mitosis to G1 phase, and CIP treatment in vitro of affinity-purified Bni5 removed the modification, indicative of phosphorylation on Bni5. The phosphorylation-deficient mutant of BNI5 (bni5-4A) was defective in both growth at semi-restrictive temperature and suppression of septin defect. Loss of Bni5 phosphorylation resulted in abnormal bud morphology and cell cycle delay at G2 phase, as evidenced by the formation of elongated cells with multinuclei. However, deletion of Swel completely eliminated the elongated-bud phenotypes of both bni5 deletion and bni5-4A mutants. These results suggest that the bud morphogenesis and mitotic entry are positively regulated by phosphorylation-dependent function of Bni5 which is under the control of Swel morphogenesis pathway.

• Mycobiology
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• 제41권3호
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• pp.139-144
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• 2013

Makgeolli is a traditional cloudy-white Korean rice wine with an alcohol content of 6~7%. The present study investigated the morphological characteristics, carbon-utilizing ability, fatty acid composition, alcohol resistance, glucose tolerance, and flocculence of Saccharomyces cerevisiae Y98-5 and Pichia anomala Y197-13, non-S. cerevisiae isolated from Nuruk, which is used in brewing Makgeolli. Similar morphological characteristics were observed for both isolated wild yeast strains; and the carbon source assimilation of Y197-13 differed from that of other P. anomala strains. Strain Y197-13 was negative for D-trehalose, mannitol, arbutin, I-erythritol, and succinic acid. The major cellular fatty acids of strain Y197-13 included C18:2n6c (33.94%), C18:1n9c (26.97%) and C16:0 (20.57%). Strain Y197-13 was Crabtree-negative, with 60% cell viability at 12% (v/v) ethanol. The flocculation level of strain Y197-13 was 8.38%, resulting in its classification as a non-flocculent yeast.

• 한국식품저장유통학회지
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• 제9권2호
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• pp.179-183
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• 2002

본 연구에서는 옥수수의 무증자 알콜발효조건을 설정하고자 반응표면분석으로 알콜 발효조건을 모니터링하였다. 그 결과 무증자 발효에 가장 적합한 효모는 S. cerevisiae GRJ이었으며, alcohol content, brix, pH 및 총산에 대하여 회귀 분석한 결과, R2는 각각 0.8852, 0.9202, 0.8806 및 0.9940이였다. 최적 알콜발효 조건은 효소제 함량 0.18%, 가수량 180%(v/w)로 예측되었으며 최적 알콜발효조건에서의 예측값은 실제 값과 유사한 경향으로 나타나 실증이 검증되었다.

• Journal of Microbiology and Biotechnology
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• 제20권10호
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• pp.1397-1402
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• 2010

Papyriflavonol A (PapA), a prenylated flavonoid [5,7,3',4'-tetrahydroxy-6,5'-di-(${\gamma},{\gamma}$-dimethylallyl)-flavonol], was isolated from the root barks of Broussonetia papyrifera. Our previous study showed that PapA has a broad-spectrum antimicrobial activity against pathogenic bacteria and fungi. In this study, the mode of action of PapA against Candida albicans was investigated to evaluate PapA as an antifungal agent. The minimal inhibitory concentration (MIC) values were 10~25 ${\mu}g/ml$ for C. albicans and Saccharomyces cerevisiae, Gram-negative bacteria (Escherichia coli and Salmonella typhimurium), and Gram-positive bacteria (Staphylococcus epidermidis and Staphylococcus aureus). The kinetics of cell growth inhibition, scanning electron microscopy, and measurement of plasma membrane florescence anisotrophy revealed that the antifungal activity of PapA against C. albicans and S. cerevisiae is mediated by its ability to disrupt the cell membrane integrity. Compared with amphotericin B, a cell-membrane-disrupting polyene antibiotic, the hemolytic toxicity of PapA was negligible. At 10~25 ${\mu}g/ml$ of MIC levels for the tested strains, the hemolysis ratio of human erythrocytes was less than 5%. Our results suggest that PapA could be a therapeutic fungicidal agent having potential as a broad spectrum antimicrobial agent.

• KSBB Journal
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• 제10권4호
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• pp.370-373
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• 1995

S.cerevisiae에 의한 에딴올 발효에셔 생성되는 부산물 인 acetic acid, acetaldehyde, glycerol, lactic acid, formic acid가 세포성장과 에탄올 생성에 미치는 영향을 고찰하였다. Acetic acid와 acetaldehyde 를 발효액 내에 투입하였을 때, 세포생장은 저해되 었으나, 에탄올 생성은 증가되었다. 한편, glycerol 과 lactic acid는 세포성장과 에탄올 생산에 거의 영 향이 없었다. Acetic acid와 acetaldehyde는 비성장 속도를 줄임과 동시에 정체기를 늘염으로써 세포성장을 저해하였다. 에단올 수율은 첨가된 acetic acid 와 acetaldehyde 농도에 비례하여 증가하였고, acetic acid $3g/\ell$, acetaldehyde $2g/\ell$ 일 때, 최대가 되었다.